import java.util.LinkedList;
import java.util.Queue;

/**
 * Created with IntelliJ IDEA.
 * Description:二叉树
 * User: Admin
 * Date: 2022-05-17
 * Time: 18:46
 */
public class BinaryTree {

    class TreeNode {
        public char val;
        public TreeNode left;
        public TreeNode right;

        public TreeNode(char val) {
            this.val = val;
        }
    }

    public TreeNode createTree() {
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');

        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        D.left = H;

        return A;
    }

    // 前序遍历
    void preOrder(TreeNode root) {
        if(root == null) return;
        System.out.print(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }
    // 中序遍历
    void inOrder(TreeNode  root) {
         if(root == null) return;

         inOrder(root.left);
        System.out.print(root.val+" ");
        inOrder(root.right);
    }
    // 后序遍历
    void postOrde(TreeNode  root) {
        if(root == null)  return;

        postOrde(root.left);
        postOrde(root.right);
        System.out.print(root.val+" ");
    }

    public int TreeSize;

    // 获取树中节点的个数
    void size(TreeNode root) {
        if(root == null) return;

        TreeSize++;
        size(root.left);
        size(root.right);
    }
    int size1(TreeNode root) {
        if(root == null) return 0;

       return size1(root.left) + size1(root.right) + 1;
    }
    // 获取叶子节点的个数
    int getLeafNodeCount(TreeNode root) {
        if(root == null) return 0;

        if(root.left == null && root.right == null) {
            return 1;
        }
        return getLeafNodeCount(root.left) + getLeafNodeCount(root.right);
    }
    public int Tree;
    void getLeafNodeCount1(TreeNode root) {
        if(root == null) return ;

        if(root.left == null && root.right == null) {
           Tree++;
        }
        getLeafNodeCount1(root.left);
        getLeafNodeCount1(root.right);
    }
    // 子问题思路-求叶子结点个数

    // 获取第K层节点的个数
    int getKLevelNodeCount(TreeNode root,int k){
        if(root == null) return 0;

        if(k == 1) return 1;

        return getKLevelNodeCount(root.left,k-1)+getKLevelNodeCount(root.right,k-1);

    }
    // 获取二叉树的高度
    int getHeight(TreeNode root) {
        if(root == null) return 0;

        int ret1 = getHeight(root.left);
        int ret2 = getHeight(root.right);


        return ret1 < ret2 ? ret2+1 : ret1+1;
    }
    // 检测值为value的元素是否存在
    TreeNode find(TreeNode root, int val) {
        if(root == null) return null;

        if(root.val == val) {
            return root;
        }

        TreeNode ret = find(root.left,val);
        if(ret != null) {
            return ret;
        }
        TreeNode ret1 = find(root.right,val);
        if(ret1 !=null) {
            return ret1;
        }
        return null;
    }
    //层序遍历
    void levelOrder(TreeNode root) {
        if(root == null)  return;
        Queue<TreeNode> que = new LinkedList<>();

        que.offer(root);

        while(!que.isEmpty()) {
            TreeNode cur = que.poll();
            System.out.print(cur.val+" ");
            if(cur.left != null) {
                que.offer(cur.left);
            }

            if(cur.right != null) {
                que.offer(cur.right);
            }
        }
    }
    // 判断一棵树是不是完全二叉树
    boolean isCompleteTree(TreeNode root) {
        if(root == null)  return false;
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);

        while(!queue.isEmpty()) {
            TreeNode cur = queue.poll();
            if(cur != null) {
                queue.offer(cur.left);
                queue.offer(cur.right);
            } else {
                break;
            }
        }

        while(!queue.isEmpty()) {
            TreeNode cur = queue.peek();
            if(cur == null) {
                queue.poll();
            } else {
                return false;
            }
        }
        return true;
    }
}
